Looper and feeding mechanism for sewing machines



C. C. SMITH ET AL Oct. 22. 1940.

LOOPER AND FEEDING MECHANISM FOR SEWING MACHINES 3 Sheets-Sheet lINVENTORS:

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(7a u 4 W ATTORNEY Oct. 22, 1940. C Q sMlTH r AL 2,219,211

LOOPER AND FEEDING MECHANISM FOR SEWING MACHINES Filed Feb. 5, 1938 3Sheets-Sheet 3 FIG-P: 41f

FIG A.

FIG II.

INVENTORS: Claicence (I. ,Siniih 23:.

.4 TTORN YS.

PATENT OFFICE v V 2,219,211 LOOPER nn FEEDING MECHANISM ron .SEWINGMACHINES Clarence C. Smith, Chicago, and George Saucr,

Bcrwyn,

Ill., assignors to Union Special Machine Company, Chicago, 111., acorporation of Illinois Application February 5, 1938, semi No. 188,837

10 Claims.

mechanism for sewing machines; and it has reference more particularly tolooping and feeding mechanism for sewing machines ofthe type wherein thelooping and feeding mechanism is disposed below the work supportingsurface and arranged to be operated from a horizontal shaft at thelevel'above the work support.

The chief aim of our invention is to secure a more perfect balancebetween the looping and the feeding elements, and at the same time toreduce in number the parts required for their actuation, with a viewtoward minimizing vibration and thereby enabling operation of the sewingmachines at higher speeds than possible heretofore, and attaining acorrespondingly increased output or production from them.

This desideratum we realize in practice, as hereinafter more fullydisclosed by arranging the looper shaft and the feed bar in parallelismand providing a double arm rocker which is medially-fulcrumed tooscillate about a transverse axis intermediate the looper shaft and thefeed bar with its opposite extremities connected to the shaft and thebar in such manner that the latter are longitudinally 'reciprocatedcontrari-- wise to induce needle-approaching and needleavoidingmovements of the loopers and feeding movements of the feed dog.

In connection with the looping and feeding mechanism wherein the loopershaft and the feed bar are longitudinally reciprocated contrariwise asabove set forth, it is a further aim of our invention to enableimpartation of oscillatory movements to the looper shaft and therebyinduce loop taking and retractive movements of the looper; and rockingmovements to the bar and in turn induce up and down or lift movements ofthe feed dog without interfering with the feed bar support againstlateral vibration and bending through provision therefor of a pivotedsleeve in which it is effectively held incident to moving endwise.

Another object of our invention is to secure the foregoing advantages inlooping and feeding mechanism whereof the component parts lendthemselves to ready manufacture and assembling at small cost.

Other objects and attendant advantages will (Cruz-215) This inventionrelates to looping and feeding appear from the following detaileddescription of the-attached drawings, wherein Fig. I is a view partly inside elevation and partly in'longitudinal section of a sewing machineembodying our improved looping and feeding mechanism.

' Fig.1]; is a plan view of the work support of the machine with itscover members removed.

Fig. III is a longitudinal sectional view of the work support.

Fig. IV is a fragmentary view showing the front end of a work supportin'plan.

Fig. V is a horizontal detail section of the rear end of the worksupport taken as indicated by the arrows VV in Fig. III.

Figs. VI, VII, VlII, IX and X are. detail cross sectional views taken asindicated respectively by the arrows VIVI, VIIVII, VIII VlII. IX-IX, andXX in'Fig. III.

, The sewing machine chosen for convenience of exemplifying ourinvention is of the feed-oftthe-arm type, generally like the oneillustrated and described in U. S. Patent #1,74l,095, granted on Dec.24, 1929, to NormanV. Christensen and Harold J. LeVesconte, in that ithas a frame with a horizontal tubular elevated portion l which isintegrally formed with a'bracket-like base 2, and a pendant hollowvertical portion 4 whereto is detachabiy connected a hollow horizontalwork-supporting arm 3, the free end of which underreaches a laterallyprojecting head 5 at the corresponding end of-said elevated tubularportion. Guided for vertical reciprocation in the head 5 is a bar 6whereto a pair'of needles l are secured at the lower end. Also confinedto axial movement in the head 5 is a vertical presser bar 8 whichcarries' a presser foot 9 at its lower end. Through suitable connections(not illustrated) up and down movements are induced in the needle bar 6from a shaft III which extends longitudinally through the tubular frame.

portion I. As shown, the shaft l0 protrudes machine where it is providedith a combined hand and belt wheel I! so that the machine may beoperatedeither manually or by power.

a Within the hollow of the vertical frame portion 4 at a levelintermediate the work support 3 and the needle actuating shaft III is aparallel countershaft II which is driven, through a pair of intermeshingspur gears l8, l9, from said needle shaft, and which is journaled atopposite ends in bearings 20, 2!, respectively set into the oppositeside walls IG and 22 of said vertical frame portion. The countershaft I1is formed with a through a bearing H at the front end of the: I

plurality of rotary actuators in the form of cranks 23, 24 and 25 whichthrough drop links 26, 21, 23' serve to Y actuate our improvedcomplemental stitch-forming and feeding mechanism in a manner presentlyexplained. The countershaft and gear construction just describedconstitutes the subject matter of a separate patent application SerialNo.-188,836 filed by us concurrently herewith.

The complemental stitch-forming and feeding means with which the presentinvention is more especially concerned is housed within the hollow ofthe work supporting arm 3, and as shown in Figs. II-X, includes alongitudinally extending shaft 36 which is journaled in spaced bearings3|, 32 and'33 at the bottom of the work support with capacity for bothendwise and oscillatory movement. Secured to the outer end of the shaft36 is aholder 34 for a pair of loopers 35 arranged to cooperate in awell known manner with the needles 1 in stitch formation. The shaft 36is reciprocated endwise to induceneedie-avoiding movements in theloopers 35 through a link 31. At one end, the link 31 is pivoted to alaterally-projecting stud 38 of a cross head 36 confined between a pairof fixed collars 46 on the looper shaft 36, and at its other end, saidlink carries a stud 4| capable of adjustment'along a longitudinal slotin the pendant extremity 42a of a double arm rocker 42 affixed to atransverse shaft 43 at a level intermediate said looper shaft and anoverlying feed bar 46. As shown in Figs.

V and x, the transverse shaft 43 has its opposite ends journaled inbearings 41, 48 whereof the former is set into one of. the side walls ofthe work arm 3, and the latter into an upstanding lug 43 within saidwork arm. From Figs. III and IX, it will be observed that the cross head39 has a downward-projection 56 which engages .within the intervalbetween longitudinally-ar ranged guide blocks 5| .at the bottom of thework arm 3. To the inner end of the looper shaft 36 beyond the bearing33 is secured a crank arm 52 with a laterally-projecting stud 53 whichpresent applicants) on June 22, 1937, a feed dog about a transverselyextending pin 58 whereof.

56. In the present construction, the feed bar 46 is supported forendwise sliding movement in a pivoted slideway having the form of asupporting sleeve 51 which is medially pivoted to rock the ends areengaged in inwardly-projecting bosses 53 and 66 at opposite sides of thework support 3. sleeve 51 to induce feeding movements of the feed dog56, through a link 6| which, atone end is pivotally connected to a head62 at the rear end of said "bar, said head having its shank 62aextending into said bar and secured by a clamp collar 63. At its otherend, the link 6| carries a clamp screw stud 64 arranged for adjustmentalong the longitudinal slot in the upward extremity 42b of the doublearm rocker 42. Integrally formed with the rocker 42 is a rear- The bar46 is reciprocated within the wardly-extending horizontal arm 420, whichcarries a ball stud whereby it .is connected to the lower end of thevertical link 21-- which extends down from the crank 24on-the-countershaft l1. Up or down or liftmovements' are communicated tothe feed dog 56 as a resultfof rocking of the sleeve 51 about the pivot;56,, such motion being imparted from the crank23 on the countershaft l1through the link 26, which, at its lower end is coupled with a ball stud66. on an arm 51a extending rearwardly from said sleeve. Rotation of thefeed bar 46 is prevented as a consequence of engagement of the squaredshank 54 of the feed dog-supporting head 55 in acorrespondingly-configured recess 66 in the outer end wall 61 of thework arm 3, see Figs. II and VII. The teeth of the feed dog 56 operatethrough the longitudinal slots of a throat plate 69 securedcantilever-fashion to the outer end of the work arm 3 by screws 10. Theparts-within the work arm 3 are accessible from above upon removal ofatop cover plate shown at 1| in Figs. III. VIII and IX, and the loopers-35 and'the feed dog 56 are exposed for the purposes of'inspection oradjustment upon withdrawal of a removable end cap indicated at 12 inFigs. I, III, IV, v: and VII.

The operation of the mechanism is as follows:

By the action of the crank 24 on the countershaft l1 upon the link 21,the mcdially-fulcrumed double 'arm rocker 42 is continually oscillated,and through it and the associated horizontal links 31 and 6|, the loopershaft 3|! and the feed bar 46 are reciprocated endwise, that is to say,the looper shaft is shifted in one direction while the feed bar isshifted in the other and vice versa. Since, as will be apparent fromFig.III, the looper shaft 36 and its appendages are so proportioned as tohave a total weight equal substantially to that of the feed bar 46 andits appendages, the endwise movements of one will be balanced by thecontrariwise endwise movements of the other. Moreover, since theretractive swing of the loopers 35 must of necessity take placeconcurrently with the rising movement of the feed dog 56 .andvice-versa. a balanced action is also had between the oscillations ofthe looper shaft 36 and of the pivoted guideway 51 in which the feed bar46 is effectively held and controlled againstlateralfiexure andvibration in its endwise movements. It accordingly follows that ourimproved looping and feeding mechanism is smooth and noiseless in itsaction and therefore favors running of the sewing machine at highspeeds. In order to adapt the machine for operation upon different kindsof material, the movements of the loopers 35 and the feed dog 56 may beincreased or decreased simply by shifting the studs 4| and 64 of thelinks 31 and 6|- respectively along the slotted extremit es of thedouble arm rocker 42, said studs being accessible for this purpose uponremoval of the screw plugs ,shown at 13 and 14 in Figs. I and X fromaccess openings in one side of the work arm 3.

Attention is also directed to the fact that the component parts of themechanism are of simple design and therefore easy to manufacture andassemble at low cost.

Having thus described our invention, we claim: 1. Looping and feedingmechanism for chain stitch sewing machines comprising a looper shaft, aparallel feed bar, a double arm rocker medially fulcrumed to oscillateabout a transverse axis intermediate the shaft and the bar, said rockerhaving slots longitudinally of its opposite extremiti'es, a link pivotedat one end to the shaft and carrying a stud at its other end adjustablealong the slot of one of the extremities of the rocker, another linksimilarly connecting the feed 5 bar with the other extremity of therocker, and means for actuating the rocker,

2. Looping and feeding mechanism for chain stitch sewing machinescomprising a looper shaft, a parallel feed bar, a support wherein thebar is confined for axial reciprocation, said support being mounted on atransverse pivot, a double arm rocker medially fulcrumed on a transverseaxis, a link connecting the shaft to one extremity of the rocker,another link connecting the feed bar to the other extremity of therocker, and means for actuating the rocker and for oscillating the feedbar support on its pivot.

3. Looping and feeding mechanism for a chain stitch sewing machinehaving a horizontal rotary shaft at a level above a horizontal worksupporting surface, said mechanism comprising a horizontal looper shaft,a parallel feed bar, a double arm rocker medially fulcrumed to oscillateabout a transverse axis intermediate the looper shaft 35 and the feedbar, means connecting the opposite extremities of the rockerrespectively with the looper shaft and the feed bar, said looper shaft,feed bar, rocker and connecting means being all beneath the worksupporting surface, and an 30 actuating connection extending down fromthe rotary shaft aforesaid to the rocker.

4. Looping and feeding mechanism for a chain stitch sewing machinehaving a horizontal rotary shaft at a level above a horizontal worksupporting surface, said mechanism comprising a horizontal looper shaft,a horizontal feed bar overlying the looper shaft and carrying a feeddog, a vertically-arranged double arm rocker medially fulcrumed tooscillate about a transverse axis 1 intermediate the looper shaft andthe feed bar,

means whereby the pendant and upwardly extending extremities of therocker are respectively coupled to the looper shaft and the feed bar,said looper shaft, feed bar, rocker and connecting 45 means being allbelow the work supporting surface, and an actuating connection extendingdown from the rotary shaft to the rocker.

5. Looping and feeding mechanism for a chain stitch sewing machinehaving a horizontal rotary IQ shaft at a level above a horizontal worksupporting surface, said mechanism comprising a horizontal looper shaft,a horizontal feed bar overlying the looper shaft and carrying a feeddog, a vertically-arranged double arm rocker medially g5 fulcrumed tooscillate about a transverse axis intermediate the looper shaft and thefeed bar, means whereby the pendant and upwardly extending extremitiesof the rocker are respectively coupled to the looper shaft and the feedbar, said Q looper shaft, feed bar, rocker and connecting means beingall below the work supporting surface, and a link extending down from anactuator crank on the rotary shaft aforesaid to the rocker. 6. Loopingand feeding mechanism for a chain stitch sewing machine having ahorizontal work supporting surface and a horizontal rotary shaft at ahigher level, said mechanism comprising a horizontal looper shaftsupported with capacity for endwise reciprocation and oscillation, ahori- 1. zontal feed bar. a support pivoted on a transverse axis andguiding the feed bar for endwise movement, is double arm rocker mediallymlcrumed to oscillate about a transverse axis intermediate the loopershaft and the feed bar, means whereby the opposite extremities of therocker are respectively connected to the looper shaft and the feed bar,said looper shaft, bar, rocker, pivoted sup- 5 port and connecting meansbeing all below the work supporting surface, and separate connectionsextending down from the rotary shaft to oscillate the looper shaft, toactuate the rocker, and to oscillate the pivoted support for the feed 10bar.

'7. Looping and feeding mechanism for a chain stitch sewing machinehaving a horizontal work supporting surface and a horizontal rotaryshaft at a higher level, said mechanism comprising a 15 horizontallooper shaft supported with capacity for endwise reciprocation andoscillation, a horizontal feed bar, a support pivoted on a transverseaxis and guiding the feed bar for, endwise movement, a double arm rockermedially fulcrumeld to 20 oscillate about a transverse axis intermediate,the

looper shaft and the feed bar, means whereby the opposite extremities ofthe rocker are respectively connected to the looper shaft and the feedbar, said looper shaft, bar, rocker, pivoted support and connectingmeans-being all below the work supporting surface, and links extendingdown from actuating cranks on the rotary shaft and connectedrespectively to a crank arm on the looper shaft, to the'rocker, and tothe pivoted support for the feed bar. a

8. The combination with looper and feeding mechanism for chain stitchsewing machines comprising an oscillating and endwise reciprocatinglooper shaft, a rocking and endwise reciproeating feed bar carrying afeed dog at one end thereof, and means for inducing simultaneous endwisemovements of said'looper shaft and feed bar in opposite directions; of amovable supporting guide in which the bar is guided in its endwise 40reciprocation, and a fixedguide which engages the feed bar beyond themovable guide and prevents said bar from rotating about its own axis.

9. The combination with looper and feeding mechanism for chain stitchsewing machines comprising an oscillating and endwise reciprocatinglooper shaft, a rocking and endwise reciprocating feed bar with a feeddog at one end thereof,and means for inducing simultaneous endwisemovements of said looper shaft and feed bar; of a movable supportingguide in which the feed bar is guided in its endwise reciprocation, anda fixed guide which engages the feed bar adjacent the feed dog, andprevents said bar from rotating about its own axis.

10. The combination with looper and feeding mechanism for a chain stitchsewing machine comprising an oscillating and endwise reciprocatinglooper shaft, a rocking and endwise reciprow eating feed bar and meansfor inducing sin ul-go taneous endwise movements of said looper'shaftand feed bar in opposite directions, of a movable guide in which thefeed bar is guided in its end-- wise reciprocation, and a fixed guidewhichv engages the feed bar beyond the movable guide and as preventssaid bar from. rotating about its own axiasaid shaft with its appendagesand said bar with its appendages being so proportioned and arranged asto substantially balance eachother in thei movements. 1

,, CLARENCE (I. SMITH. GEORGE BAUER.

